1. Technical Field
The disclosure is related to a gas barrier substrate and a package of an organic electro-luminescent device.
2. Related Art
Compared with general rigid substrates, flexible substrates have applications in a wider range of areas. Flexible substrates have advantages such as flexibility, portability, compliance with safety standards, and wide range of applications, but they also have disadvantages such as inferior heat resistance, inferior water and oxygen resistance, inferior chemical resistance, and greater thermal expansion coefficients. Since conventional flexible substrates cannot completely block water vapor or oxygen, aging of electronic devices on the substrate is accelerated, thereby shorting the lifespan of the electronic devices. Commercial requirements are hence unable to be fulfilled. In order to make flexible substrates have better water vapor and oxygen resistance, conventional art has provided a flexible substrate with a gas barrier layer for enhancing reliability of the electronic devices. FIGS. 1 and 2 are illustrated and conventional flexible gas barrier substrate is described as follow.
FIG. 1 is a schematic cross-sectional diagram of a conventional flexible gas barrier substrate. Please refer to FIG. 1. A conventional flexible gas barrier substrate 100 is generally fabricated on a carrier C and includes a substrate 110 and a gas barrier layer 120. The gas barrier layer 120 only covers a top surface 110a and a sidewall 110b of the substrate 110, and a bottom surface 110c contacts the carrier C. As shown in FIG. 1, when the flexible gas barrier substrate 100 is detached from the carrier C, the bottom surface 110c of the substrate 110 is exposed. Since the bottom surface 110c of the substrate 110 is not covered by the gas barrier layer 120, the flexible gas barrier substrate 100 warps seriously due to imbalance of stress.
In order to resolve the warp problems of the flexible gas barrier substrate, the conventional art has provided a solution, which is illustrated in detail in FIG. 2.
FIG. 2 is a schematic cross-sectional diagram of another conventional flexible gas barrier substrate. Please refer to FIG. 2. A conventional flexible gas barrier substrate 200 is also fabricated on the carrier C and includes a substrate 210, a first gas barrier layer 220, and a second gas barrier layer 230. The first gas barrier layer 220 only covers a bottom surface 210c of the substrate 210, and the second gas barrier layer 230 covers a top surface 210a and a sidewall 210b of the substrate 210 and a sidewall 220a of the first gas barrier layer 220. As shown in FIG. 2, the second gas barrier layer 230 is bonded with the sidewall 220a of the first gas barrier layer 220. However, as limited by the thickness of the first gas barrier layer 220, the bonding strength between the second gas barrier layer 230 and the sidewall 220a of the first gas barrier layer 220 is insufficient. Therefore, when the flexible gas barrier substrate 200 is bended, the second gas barrier layer 230 which covers the sidewall 210b may be easily broken. Moreover, if the thickness of the first gas barrier layer 220 is increased for increasing the bonding strength between the second gas barrier layer 230 and the sidewall 220a of the first gas barrier layer 220, the overall thickness of the flexible gas barrier substrate 200 may increase.
In light of the above, one of the issues focused on by developers is how to effectively improve the gas barrier characteristic of the flexible gas barrier substrate without increasing the overall thickness of the flexible gas barrier substrate.